I hope you don't mean a NAZI flag...although if you mean that, that is hilarious.
I always thought a Scottish flag St. Andrews or the rampant lion would be cool, just depends on the base color though.
and F no to putting an American flag on a mini, I know someone is gonna jump down my throat about that. For some reason that would annoy me to see that, overly patriotic Americans are the most annoying people alive. I live in the south, so that usually means they are just a racist that thinks driving anything other then a ford truck is a cardinal sin.